An enzyme in the bacterium that Brock discovered was used by Kary Mullis to create the polymerase chain reaction (PCR) that is part of Covid-19 tests.
(p. B11) Thomas Brock, a microbiologist, was driving west to a laboratory in Washington State in 1964 when he stopped off at Yellowstone National Park.
. . .
What fascinated him, on what would be the first of many trips to Yellowstone, were the blue-green algae living in a hot spring — proof that some life could tolerate temperatures above the boiling point of water.
It was the beginning of research that led to a revolutionary find in 1966: a species of bacteria that he called Thermus aquaticus, which thrived at 70 degrees Celsius (158 degrees Fahrenheit) or more.
. . .
The yellow bacteria — discovered by Dr. Brock and Hudson Freeze, his undergraduate assistant at Indiana University — survive because all their enzymes are stable at very high temperatures, including one, Taq polymerase, that replicates its own DNA. It proved essential to the invention of the process behind the gold standard in coronavirus testing.
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When he arrived at Yellowstone, he did not have grandiose ambitions.
“I was just looking for a nice, simple ecosystem where I could study microbial ecology,” he said in an interview for the website of the University of Wisconsin, Madison, where he was a professor of natural sciences in the department of bacteriology from 1971 to 1990. “At higher temperatures, you don’t have the complications of having animals that eat all the microbes.”
Stephen Zinder worked with Dr. Brock as a student from 1974 to 1977, a period that included Dr. Brock’s last summer of work at Yellowstone and his research into the ecology of Wisconsin’s lakes, including Lake Mendota in Madison.
“He had an encyclopedic knowledge of microbiology and science in general,” said Dr. Zinder, now a professor of microbiology at Cornell University. “He was always learning and picking up new things.” He added, “I think his real ability was to see things simply and to figure out simple techniques to find out what the organisms were doing in their environment.”
For the full obituary, see:
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(Note: the online version of the obituary was updated April 26, 2020, and has the title “Thomas Brock, Whose Discovery Paved the Way for PCR Tests, Dies at 94.”)